This invention involves compositions and a process for drilling or stimulating of subterranean reservoirs including but not restricted to shale, tight gas, coal, conventional and non-conventional reservoirs. The composition of this invention is composed of ingredients that are considered to be non-toxic, biodegradable and derived from “green” or renewable resources.
The growing need for oil coupled with the decline in primary production of oil has required the need for more novel and efficient methods of recovering residual oil. These methods are generally referred to as improved oil recovery (IOR) or well stimulation. Many flow back aids have been developed and discussed in the prior art to help recover injected fluids after fracturing. The flow back aids benefits the production by reducing damage due to phase trapping, enhance mobilization of the oil and gas, help to increase the regained permeability and improve the oil/gas recovery. Flow back aid formulations generally include one or more anionic, nonionic or amphoterics surfactants, along with solvents and co-surfactant that are in the solution or microemulsion form. The various flowback aids are discussed by Howard et al. in SPE paper 122307. Also Panga, et al. discusses the wettability alteration in SPE 100182. Pursley et al. U.S. Pat. No. 7,380,606 discloses a microemulsion well treatment formed by combining a solvent-surfactant blend with a carrier fluid. In the preferred embodiments, the solvent-surfactant blend includes a surfactant and a solvent selected from the group consisting of terpenes and alkyl or aryl esters of short chain alcohols. Surfactants include ethoxylated castor oil, polyoxyethylene sorbitan monopalmitate and polyethylene glycol. Additionally, Isopropyl alcohol and triethylene glycol are used in some cases. Penny and Pursley in SPE 107844 give field and laboratory data supporting the effectiveness of microemulsions in low perm shales, coalbed methane and tight sandstone reservoirs.